Cloth bleaching operation



Sept. 19, 1950 H. M. SCHMlTT I 2,522,900

CLOTH BLEACHING OPERATION Filed June 16, 1945 3 Sheets-Sheet 1 FIG. I

INVENTOR. HENRY M. SCHMITT I I I I ATTORNEY.

Sept. 19, 1950 H. M. SCHMITT CLOTH BLEACHING OPERATION a Sheets-Sheet 2Filed June 16, 1945 INVENTOR. HENRY M. SCHMITT ATTORNEY.

p 1950 I H. M. SCHMITT 2,522,900

CLOTH BLEACHING OPERATION Filed June 16, 1945 5 Sheets-Sheet 3 i I 29 W.Imum mun I [Emmi a INVENTOR. 1 HENRY M. SCHMITT F I G. 3

2 ATTORNEY Patented Sept. 19, 1950 CLOTH BLEAQHING OPERATION Henry M.Schmitt, Glenside, Pa., assignor, by mesne assignments, toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn, acorporation of Delaware Application June 16, 1945, Serial No. 599,825

2 Claims. 1

The present invention relates to a bleaching system of the known type inwhich cloth is bleached by subjecting it to a plurality of washing,chemical treating, steaming and drying operations, one after another insome definite order, and including at least one operation in which thecloth in a water wet or saturated condition is passed into and through acaustic bleaching liquor bath.

The general object of the present invention is to provide an improvedmethod of, and improved apparatus for automatically controlling thewater content, or degree of saturation of the cloth passing into saidbath, and for controlling the rate of addition to the bath ofconcentrated bleaching liquid which unites with the water carried intothe bath by the cloth to form a suitably dilute bath liquor. By suitablycontrolling the cloth water content and the addition of the concentratedbleaching liquid to the bath in accordance with the present invention,it is possible to maintain the desired volume and composition of thebath liquor.

A further object of the invention is to automatically control the bathliquor content, or degree of saturation, of the cloth leaving the saidbath so as to insure uniform operation and the avoidance of bath liquorwaste in the subsequent treatment of the cloth.

In the preferred form of the invention, I utilize air control apparatuswhich may be of well known commercial form, to maintain a controllingair pressure proportional to the volume of bath liquor in the bath, andutilize variations in that controlling pressure to regulate thecompression or r wringer action to which the cloth entering the bath issubjected by so-called nip rolls between which the cloth passes, and toregulate the feed of a chemical bleaching agent to the bath.

In the preferred form of the invention, the bath liquor content, ordegree of saturation, of the cloth leaving the bleaching liquor bath isregulated by regulating the compression or wringer action of a pair ofnip rolls between which the cloth is passed immediately after leav ingthe said bath. In the preferred form of the present invention, the lastmentioned regulating action is obtained by the use of air controlapparatus of known type combined in a so-called dual measuring and aircontrol instrument with the first mentioned air control apparatus.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and formingapart of this specification. For a betterunderstanding of the invention,however, its advantages, and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described preferred embodimentsof the invention.

Of the drawings:

Fig. 1 is a view diagrammatically illustrating a portion of a bleachingsystem;

Fig. 2 diagrammatically illustrates control apparatus associated with asaturator element shown in Fig. 1, and

Fig. 3 is an elevation on a larger scale of an instrument shown in Fig.2.

In Fig. 1, I have diagrammatically illustrated the final portion of acloth bleaching system of conventional type. The apparatus showndiagrammatically in Fig. 1 comprises means for moving a cloth web Isuccessively through washing devices 2, a bleaching liquor bath held ina saturator tank or vessel 3, a so-called J-box 4, a

pair of washing rolls 5, a multiplicity of drying cylinders or cans 6,and rolling apparatus 1 in which the bleached and dried fabric is woundabout a suitable spool l. The cloth passes into the saturatorimmediately after passing between nip rolls 8 and 9, and passes betweennip rolls [0 and H immediately after passing out of the saturator 3. Inaddition to the nip rolls 8, 9, I0 and H, the apparatus shown in Fig. 1comprises numerous rolls employed to effect the movement of the cloth,and to define its path of movement, through the apparatus shown in Fig.1, but as such rolls are conventional and form no part of the presentinvention, they need not be further referred to herein.

A bleaching system of the conventional type illustrated includesapparatus, not shown herein, which acts on the cloth before it reachesthe washers 2 shown in Fig. 1 and may comprise a sodium hydroxide bath,a J-box, and in many cases an acid bath as well as cloth washers.

In the operation of the apparatus shown in Fig. 1, the pressure orwringer action of the nip rolls 8 and 9 on the cloth passing betweenthem, determines the water content, or degree of saturation, of thecloth passing into the bath in the saturator 3. In normal practice, theweight of the water carried by the cloth entering the bath is ordinarilybetween and of the weight of the cloth. Similarly, the pressure betweenthe nip rolls l0 and I l determines the bath liquor, content or degreeof saturation of the cloth passing away from the saturator 3. In normalpractice, the weight of the bath liquor carried out of the saturator bythe cloth should be approximately equal to the weight of the cloth.

In the J-box l, the cloth is allowed to fold as shown so as to suitablyprolong the detention period during which each unit of-length of thecloth is within the J -boX 4. The cloth is subjected to a steamingaction in the J -bOX d which acts on the bleaching liquor carried by thecloth and opens up the cloth fibres. The bath liquor in tank 3 is thefinal bleaching agent, and the bleaching operation will not be efficientif the cloth carries an inadequate amount of bath liquor in the J-boxbut if the cloth carries more bath liquor into the J-box 4 than isrequired for efiicient bleaching, bleaching liquor is wasted and thebleaching operation cost rises.

In the conventional bleaching system illustrated, the bleaching agent inthe saturator 3 is usually sodium peroxide (NazOz). As shown in Fig. 2,it is supplied in concentrated liquid form by feed pipe E5 to the inletof a pump it which discharges through pipe ll, and a manually operablevalve l 8, to the inlet of a three way valve E9. The latter has oneoutlet discharging through pipe to the saturator 3, and a second outletconnected to pipe 2! which returns the supply pipe l5 liquid passed bythe pump iii to the valve I9 when the adjustment of that valve preventssome or all of the liquid received from passing through pipe 2t to thesaturator. As shown, the valve l9 includes an actuator of the fluidpressure motor type to the pressure or diaphragm chamber [9A, of which acontrolling air pressure is transmitted by'a pipe 22.

The pressure of the nip rolls 8 and ii against the cloth passing to thesaturator 3, is controlled by the pressure in the pressure or diaphragmchamber 23 of a pressure regulator of the fluid pressure motor type.Said regulator includes a strut or rod 24 which is longitudinallyadjusted by varia tions in fluid pressure in the chamber 23 and has itslower end connected to bearing blocks '25. The latter are mounted forvertical movement in a guideway 2b in which the trunnion end portions 9of the nip roll 9 are journalled. In the arrangement shown, thecontrolling air pressure transmitted through the pipe 22 to the pressurechamber lSA of the valve i9, is also transmitted through a pipe Zl tothe pressure chamber 23 associated with the nip rolls 8 and 9.

The pressure between the nip. rolls in and l l is controlled by meanscomprising parts 23, 2d, 25' and 26 similar to the previously mentionedparts 23, 24, 25 and 26, respectively, and associated with the nip rollI l, as said parts 23-26 are associated with the nip roll 9.

The controlling pressure transmitted to the pressure chambers WA and bythe pipes 22v and 27-, respectively, is established by a controlinstrument 28 and is transmitted from the latter through a pipe 25 tothe pipes 22 and 2i. The controlling pressure transmitted to thepressure chamber 23 is also established in. the instrument and istransmitted therefrom to the chamber 23 by the pipe 38. As hereinafterexplained, the instrument 28 includes separate instrumentalities forestablishing the controlpressures transmitted by the pipes 29 and (it.

As shown in Fig. 3, the instrument 28 is of the type known as a dual aircontroller and. includes two air control units 3 l and 32. The unit 3|includes follow-up and automatic compensating or reset provisions whichmay be, andare conventionally shown as, of a type and form dis- Closedin the Moore Patent 2,125,081. The con- 4 trol unit 32 is of theso-called full throttler type which includes follow-up provisions but noautomatic compensating or reset provisions, and which may be, and asconventionally shown is, of a type disclosed in said Patent 2,125,081.

Air under suitable pressure is supplied to the instrument 23 for theoperation of its air control mechanisms through branches 3t and 31 of anair supply pipe 35. Another branch 38 of the pipe supplies air through aneedle valve 3% and flow indicator id to a level measuring pipe ll. Thelatter extends down into the bath liquor in the tank 3 and has its lowerend t2 open and well below the minimum working liquid level in the tank.The upper end of the pipe extends into the casing of the instrument 2tand is therein connected to a bellows type pressure responsive element il of well known type. The slow flow of air into the pipe i l from thepipe 35 permitted by the valve 39 maintains a pressure in the pipe llcorresponding to the bath liquor head or hydraulic pressure at the levelof the open lower end 42 of the pipe ii. The air pressure transmitted bythe pipe li to the device ie, is thus proportional to, and is a measureof, the height of liquid level in the tank 3. The flow indicator do maybe a so-called bubbler through which air is bubbled so that the rate ofair flow is indicated by the number of air bubbles formed per unit oftime.

The variations in the pressure transmitted by the pipe ii to theresponsive device 44 expand and contract the bellows M of element 44 andthereby oscillate a lever 45 which has one end connected to, andlongitudinally adjusts, a link 46. The link 46 is the actuating elementof a. recording and control unit included in a mechanism assembly 13 andcomprising a pen arm 41 which is angularly adjusted, and a control link58 which is longitudinally adjusted, by the longitudinal adjustments ofthe link 46. The longitudinal adjustments of the link 48 turn a valveoperating lever d9 about its pivot 56) and thereby cause a flapper valve5| to approach or move away from the bleed orifice in the adjacent endof a bleed nozzle 52. The latter constitutes one end section of a pipewhich has its other end connected to the air supply pipe branch 38through a device 53. The latter includes a flow restricting orifice andusually includes an air filter. In consequenceof the flow restriction inthe device 53, the pressure in the bleed nozzle is varied by themovement of the flapper valve away from and toward said nozzle, betweena minimum which may be a pound or so per square inch, and a maximumwhich is the full pressure in the supply pipe 35, and may be of theorder of 17 pounds or so.

The varying control pressure in the nozzle 52 is transmitted throughdevice 53 to a pilot valve ki l. The latter also receives air throughthe device 53 from the branch 36 of the supply pipe 35 at the pressurein the latter. The air thus received. is utilized in maintaining apressure in a pipe 55 which is proportional to the pressure in the bleednozzle 52. The pipe 55 is connected to, and thereby determines thepressure in the pipe 29 connected through branches 22 and 21 to thepressure motor chambers ISA and 23. The pipe 55 also transmits the pilotvalve pressure to the follow-up mechanism 56 of the air controller unit(ii. That follow-up mechanism operates, following each adjustment of theflapper valve 5! produced by a longitudinal movement of the link 38, toadjust the supporting pivot of the lever 49 in the direction toeliminate a portion I of the said adjustment of the flapper valvepreceding the operation of the follow-up mechanism. The unit 3| alsoincludes a reset or compensating mechanism 6|, whichtends to eliminate,more or less slowly, each adjustment Or" the valve effected by thefollow-up mechanism 56. The rate at which the compensating or resetadjustment is effected may be regulated by adjustment of the rotatableadjustment device 62.

The overall effect of the adjustment in the pressure transmitted fromthe instrument 28 to each of the pressure motor chambers 9A and 23, isto increase or decrease the amount of bath liquor in the tank 3,following any decrease or increase, respectively, in the air pressure inthe pipe 4|. As shown, the instrument 28 includes a gauge 5'! which maybe calibrated to show either the pressure in the pipe 4|, or thepressure in the pipes 29 and 55.

The adjustments of the flapper valve 5|, effected as above described,tend to maintain a normally constant quantity of bath liquor in the tank3. That constant quantity can be varied, or regulated, by the rotationof a control point .adjustment element 58 included in the mechanismassemblage 43. The effect of that adjustment is to change the relationbetween the longitudinal adjustments of the links 46 and 48. An index orcontrol point setting pointer 59 is adjusted by the adjustment of thedevice 58 and indicates on the record chart of the instrument 28, theamount of liquor which the apparatus tends to maintain in the tank 3.The thrattling range, or ratio between the longitudinal movements of thelinks 46 and 48 can be adjusted by rotating an adjustment device 60.

In respect to the above mentioned features through which the instrument28 varies the pressure in the pipe 29 in response to a variation in thepressure transmitted to the element 44, the apparatus shown does notdiffer significantly from mechanism fully disclosed in the abovementioned Patent 2,125,081 and now in extensive use in this country.

The air controller unit 32 differs in essential principle from the unit3| only in that it omits the automatic mechanism of the unit 3|. Asshown in Fig. 3, the mechanism associated With the unit 32 comprisesparts 64 to 80 corresponding respectively to the previously mentioned iparts M to 6B. The unit 32 also includes manual reset means including arotatable adjusting ele ment 8|. The unit 32 does not dififer inprinciple and need not differ significantly in form from the so-calledfull throttler unit illustrated and described in prior Patent 2,125,081.The lever and linkage units mounted in the housing 43 and respectivelyassociated with the air controller units 3| and 32 are similar to oneanother and the two pen arms t! and 61 turn about adjacent axes.

The general mode of operation of the invention in the form disclosed maybe summarized as follows. An increase or decrease in the height ofliquid level in the saturator tank 3 results in an increase or decreasein the air pressure in pipe 4|. An increase in that pressure results inan angular adjustment of the lever 45 which through the link 58 andlever 49 causes the flapper 5! to approach the nozzle 52 and increasethe pressure in the nozzle 52. The pressure increase in the nozzle 52causes a corresponding increase in the pressure in the pipes 55 and 29.An increase in the pressure in pipe 29 acts through the pressure chamber23 to increase the pressure between the nip rolls 8 and 9. That increasein roll pressure wrings more water out of the cloth I passing to thesaid rolls with the result that the cloth carriesless water into thesaturator tank 3.

The pressure increase in the pipe 29 also acts through the pressurechamber. |3A of the threeway valve H) to adjust the latter so as to.interrupt or reduce the passage of the concentrated bleaching agentthrough the pipe 20 to the tank 3, while correspondingly increasing theamount of bleaching agent returned from the valve l9 through the pipe 2|to the feed pipe I5. The reduction in the amount of water carried intothe bath by the cloth and the amount of bleaching agent passed into thetank through the pipe 28 checks the rise in liquid level in the tank 3.Conversely, on a decrease in the liquid level in the tank 3, theresultant decrease in the pressure transmitted to the instrument 28through the pipe 4|, correspondingly decreases the pressure transmittedthrough pipe 29 and its branches 22 and 2'! to the pressure chambers ISAand 23.

The effect of the pressure reduction in said chambers is to increase theamount of bath liquor passing to the saturator from the valve l9 throughthe pipe 20 and to increase the amount of water carried into the bath bythe cloth I, The instrument 28 thus operates in response to variationsin the pressure in the pipe 4| to effect adjustments tending to holdthat pressure constant and thereby maintain a predetermined height ofliquid level in the tank 3. The height maintained depends upon theadjustment of the control point adjusting device 58.

The apparatus described, when properly calibrated with respect to thecharacter of the cloth being bleached and other conditions of operation,will proportion the amounts of water and concentrated bleaching agentsupplied to the tank 3 as required to maintain the composition of thebath liquor substantially constant. If the amounts of water andbleaching agent passing to the tank are not properly proportioned thebath liquor in the tank will more or less slowly increase or decrease instrength. Such variations in the strength of the bath liquor may becompensated by suitable manual calibrating adjustments of the apparatus.Such compensation may be effected, for example, by varying the operativelength of the threaded connection 24'. between the bearing blocks 9 forthe nipper roll 9 and the diaphragm in the pressure chamber 23.Alternatively, a suitable corrective effect may be obtained byincreasing the tension. of the spring, not shown, but invariablyprovided in a fluid pressure motor of the charactershown, to oppose andpartially neutralize the tendenc of the pressure in the chamber 23 tolower the roll 3.

The operative purpose and effect of the control action of the instrument28 on the pressure in the chamber 23 is to maintain the pressure betweenthe exit nip rolls Ill and II constant under any particular condition ofoperation, and to vary that pressure readily and accurately whenoperating conditions change. Such adjustment of the pressure transmittedto the pressure chamber 23 is effected by adjustment of the controlpoint adjustment device 18 of the instrument 28. A definite adjustmentof the pressure between the exit nipper rolls l0 and II is customarilyrequired whenever the character of the cloth treated is changed. Forexample, the amounts of bath liquor which should be carried into the3-1001; 4 by rayon velvet and canvas "are quite different.

While in accordance with the provisions of the "statutes, Ihave'illustrated and described the best form of embodiment of myinvention now known to me, it will be apparent tothose skilled in vtheart that changes may be made in the form of the apparatus disclosedwithout departing'from the spirit of my invention as set forth in theappended claimsand that in some cases certain features of my inventionmay be used to advantage without a corresponding use of other features.

Having now described 'my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In the cloth bleaching operation in which water wet cloth is passedcontinuously'into and through -a bath of bleaching liquor, the method ofregulating the volume while maintaining the 8 ing the cloth passing awayfrom the bath to reduce the reduction in the volume, of the liquor bathproduced by the movement of the cloth through and away from the bath.

2. A method as specified in claim 1, in which the amount of watercarried into the bath by the cloth is varied by decreasing andincreasing the pressure between a pair of nip rolls passing the cloth tosaid bath, in accordance with decreases and increases, respectively, inthe bath level height.

HENRY M. SCI-IMITT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,125,081 Moore July 26, 19382,344,066 Campbell et a1 Nov. 9, 1943 2,382,726 Korte et a1 W Aug. 14,1945 OTHER REFERENCES Buifalo, Continuous Peroxide Bleaching, Am.Dyestufi Reporter, Aug. 28, 1944, pages 365-368 and 380.

